The early detection of diseases including cancer requires multiplex measurements of key protein biomarkers in biological samples. The availability of high-affinity, highly selective molecular moieties that recognize biomarkers from complex biological mixtures is a critical component for accurate detection of proteins that may indicate disease.
Akt mediates signal transduction from the plasma membrane (cytokine receptors, GPCRs) to downstream effector molecules that control cell growth, apoptosis, and translation (Vivanco 2002). Based on its ability to block apoptosis and thereby promote cell survival, Akt overexpression and/or hyperactivation is implicated in many types of cancer (Altomare 2005). Therefore, Akt provides an attractive target as a biomarker for specific cancer types, as well as a potential therapeutic. Most current biomarker assays utilize antibodies. It is challenging to produce stable antibodies for complex targets. Thus, there is a need in the art for synthetic, stable capture agents that can be used reproducibly and effectively in bioassays and as a therapeutic treatment.